Alright so my opinion is to try and get the older cards (from first shards event) if possible, the event tab says that those 3 will be available for the last time. You should be able to get Himorogi(600 shards) and Kodama (300). If your able to get up to 1500 total you could get damocles(900) instead of kodama.

If you really want reveals that's your choice but personally I wouldn't do that over cards (generally you get enough from events to break even with revival/event getcha tickets.

Don't buy sr wild 1s! Instead if you really want wilds buy ex-wilds and give them to kurito. Worst case you'll get a 3wild from it but there's better rewards to (puddings ect). You can Look at the thread about kurito and try to get into different brackets if you want specific rewards. Personally I'm gonna dump all my extra shards into ex-wilds. Also if your really starved for wilds throw some r-gatchas at kurito for some 3 sr wilds.

Also for a strategy I'd recommend saving your e-gatchas from other events for this one so that you can catch up, assuming we have another, since it seems like the new 3 cards might be back for the next shards event, and you'll be back in the same situation as this one.

For gambit you probably wont need to spend any tickets if your able to place in the top 1k of this since we should get the sr beta, I think, as the reward. Also make sure you save enough sr wilds to max out the reward so that you get the maximum bonus possible.

As for the EG event having a 1-2 slayers is only sort of helpful but you wont be bringing down big SEG without all of them and a high base sed so I wouldn't worry to much about that.